Flexible mat forming system and method

ABSTRACT

In an exemplary embodiment, a system for forming a flexible mat having an open mesh embedded in and interconnecting a plurality of blocks of a hardened paste includes a rotating drum having a plurality of mold cavities about an outer periphery thereof that receive a hardenable paste; a sheet of the open mesh that is fed over the mold cavities so that the mesh is embedded in the hardenable paste deposited in the mold cavities; and a flexible sheet that is placed against the outer periphery of the drum over the mold cavities containing the hardenable paste and the sheet of open mesh of the rotating drum to retain the hardenable paste within the mold cavities and retain the open mesh embedded in the hardenable paste as the hardenable paste solidifies to form the flexible mat.

TECHNICAL FIELD

The present disclosure relates to systems and methods for formingflexible tied block mats, and more particularly, to systems and methodsfor forming continuous flexible tied block erosion control mats.

BACKGROUND

Erosion is a natural process in which meteorological elements such asrain, wind, and snow remove soil, rock, and dissolved material from onelocation on the Earth's crust and transport it to another location.While such erosion is a natural process, certain localized humanactivity increases the rate of erosion to many times that at whicherosion occurs naturally. Land surfaces adjacent man-made structuressuch as canals, roads, reservoirs and ponds, and artificially createddrainage channels and other waterways are particularly susceptible toerosion because naturally occurring indigenous vegetation is removed inorder to form the structures.

Erosion can be mitigated in these areas by remediation of the landsurface adjacent the canal, road, or channel by planting vegetation toreplace the vegetation that was stripped away during construction.However, there is a time interval between the planting of thereplacement vegetation and the point at which the replacement vegetationis sufficiently developed to prevent further erosion of surface soilduring which further erosion may occur.

Efforts have been made to retain the surface soil in place in theseareas until such time as vegetation can mature to the point where theroot structure of the vegetation retains the soil in place. An exampleof such material is the flexible mat structure disclosed in U.S. Pat.No. 6,793,858 titled “Method and Apparatus for Forming a Flexible MatDefined by Interconnected Concrete Panels,” the entire contents of whichare incorporated herein by reference. That patent discloses a flexiblemat structure in the form of spaced, interconnected concrete panels orblocks held together by an open mesh of a polymeric material.

The flexible mat structure may be made by depositing concrete in theblock-shaped mold cavities formed in the surface of a rotating drum andembedding in the concrete material the open mesh structure. While themethod is effective, there is a need to introduce additionalefficiencies in the manufacture of such flexible mat structure.

SUMMARY

The present disclosure describes a flexible mat forming system andmethod in which improvements have been made to increase the quality ofthe flexible mat product produced and the efficiency in the process ofmanufacturing the flexible mat. One type of mat produced by the processand system is known as a tied block mat, in which blocks of cement arecast in a pattern onto a sheet of geogrid. Such a tied block mat isideal for applying to the ground adjacent airport runways, taxiways andterminals, roadbeds, and the banks of reservoirs, canals, rivers andother waterways, shorelines, and any sloped surface to control erosion.In some embodiments, the system and process produces a tied block matthat is sufficiently sturdy to function as a drivable surface.

In one embodiment, a system for forming a flexible mat having an openmesh embedded in and interconnecting a plurality of blocks of a hardenedpaste includes a rotating drum having a plurality of mold cavities aboutan outer periphery thereof that receive a hardenable paste; a sheet ofthe open mesh that is fed over the mold cavities so that the mesh isembedded in the hardenable paste deposited in the mold cavities; and aflexible sheet that is placed against the outer periphery of the drumover the mold cavities containing the hardenable paste and the sheet ofopen mesh of the rotating drum to retain the hardenable paste within themold cavities and retain the open mesh embedded in the hardenable pasteas the hardenable paste solidifies to form the flexible mat.

In another embodiment, a system for forming a flexible mat having anopen mesh embedded in and interconnecting a plurality of blocks of ahardened paste includes a frame; a cylindrical drum rotatably mounted onthe frame and contacting the ground, the drum having a plurality of moldcavities about an outer periphery thereof that receive a hardenablepaste; a sheet of the open mesh that is carried on a support mounted onthe frame, the open mesh fed over the mold cavities so that the mesh isembedded in the hardenable paste deposited in the mold cavities; and aflexible sheet that is carried on a roll mounted on the frame, the sheetplaced against the outer periphery of the drum over the mold cavitiescontaining the hardenable paste and the sheet of open mesh and extendingdownwardly to a pinch point between the drum the ground to retain thehardenable paste within the mold cavities and retain the open meshembedded in the hardenable paste as the hardenable paste solidifies toform the flexible mat.

In yet another embodiment, a method for forming a flexible mat having anopen mesh embedded in and interconnecting a plurality of blocks of ahardened paste includes rotating a drum having a plurality of moldcavities about an outer periphery thereof; depositing a hardenable pastein the mold cavities; feeding a sheet of the open mesh over the moldcavities so that the mesh is embedded in the hardenable paste depositedin the mold cavities; and placing a flexible sheet that is placedagainst the outer periphery of the drum over the mold cavitiescontaining the hardenable paste and the sheet of open mesh to retain thehardenable paste within the mold cavities and retain the open meshembedded in the hardenable paste as the hardenable paste solidifies toform the flexible mat.

Other objects and advantages of the disclosed flexible mat formingsystem will be apparent from the following description, the accompanyingdrawings, and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic, side elevational view of an embodiment of thedisclosed flexible mat forming system;

FIG. 2 is a schematic, front elevational view of the flexible matforming system of FIG. 1;

FIG. 3 is a detail perspective view of the flexible mat forming systemof FIG. 1, showing the retaining plate;

FIG. 4 is a perspective view of the flexible mat forming system of FIG.1, taken from the rear of the hopper and drum;

FIG. 5 is a detail showing an embodiment of a rotating auger locatedwithin the hopper of the flexible mat forming system of FIG. 1;

FIG. 6 is a detail perspective view of a section of the hopper of FIG.5;

FIG. 7 is a detail perspective view showing a portion of the bottomplate of the hopper of the flexible mat forming system of FIG. 1;

FIG. 8 is an end elevation of the flexible mat of FIG. 1, formed into aroll;

FIG. 9 is a schematic side elevation of another embodiment of theinvention; and

FIG. 10 is a schematic side elevation of a movable frame or bridge forseparating the flexible mat from the flexible sheet.

DETAILED DESCRIPTION

The disclosed flexible mat forming system, generally designated 10, isshown in FIGS. 1, 2, and 4. The system 10 may include a frame 12 onwhich is mounted an elongate, rotatable cylindrical drum 14. The drum 14may be rotated by a motor 16, which in embodiments may be an electricmotor or a hydraulic motor, in which case the system 10 isself-propelled, or assists in propelling itself. The motor 16 may rotatethe drum in a counterclockwise direction, as indicated by arrow A inFIGS. 1 and 4. In other embodiments, system 10 does not have a motor 16,but instead the drum 14 rests on the ground 66 and rotates in thedirection of arrow A as a result of friction with the ground from theframe 12 being pulled over the ground, which in FIG. 1 would be to theleft. In an embodiment, the frame 12 may include a pair of horizontalbeams 18, 20 on which the drum 14 is rotatably mounted, for example by ajournal bearing 17.

As shown in FIG. 4, in an exemplary embodiment, the drum 14 includes aplurality of transverse rows 22 of mold cavities 24 that are formedabout the outer periphery, or cylindrical outer surface, of the drum. Inother embodiments, the mold cavities 24 are arranged in a pattern orpatterns on the drum. In embodiments, the patterns are selected from arectilinear, transverse row of the mold cavities, a staggered pattern ofthe mold cavities, a checked pattern of the mold cavities, a randompattern of the mold cavities, a running bond pattern of the moldcavities, and combinations of the foregoing. With such embodiments, theterm transverse row 22, as used herein, includes any spacing orarrangement or pattern of the mold cavities 24 along the length of theouter periphery of the drum 14, including the aforementioned patterns,and is not limited to a rectilinear row parallel to a central rotationalaxis of the drum 14.

Accordingly, the drum 14, which in embodiments takes the form of anelongated cylinder, is a form having mold cavities 24. In embodiments,the mold cavities 24 may be shaped to receive hardenable paste 25 from achute 27 (see FIGS. 1 and 2) from the drum of a concrete transporttruck, or from a concrete pump, or from a concrete mixer trailer, andform the hardenable paste 25 blocks 76, which in embodiments may besquare at their base. For example, the mold cavities 24 may be shaped toform pyramidal blocks 76 of hardenable paste 25 received from the hopper26 having square bases 6½″×6½″ and 2¼″ high, although the mold cavitiesmay have other shapes and dimensions. For example, the mold cavities 24may be shaped to form blocks 76 having shapes selected from rectangular,square, hexagonal, octagonal, round, elliptical, irregular, andcombinations of the foregoing.

As shown in FIGS. 1, 2, and 4, the system 10 also may include anelongate hopper, generally designated 26, adjacent the drum 14. In anembodiment, the hopper 26 is positioned directly above the drum at the12 o'clock position, such that the hopper is positioned above anuppermost one of the plurality of transverse rows 22 of mold cavities24. In other embodiments, the hopper 26 is positioned relative to thedrum 14 upstream of the 12 o'clock position, for example at the 2o'clock position, and in still other embodiments, the hopper ispositioned relative to the drum 14 downstream of the 12 o'clockposition, for example at the 10 o'clock position. In other embodiments,the hoper 26 is positioned adjacent the drum 14 in locations between the3 o'clock position and the 9 o'clock position.

In an embodiment, the hopper 26 is shaped to receive a hardenable paste25 and deposit the hardenable paste into mold cavities 24 facing thehopper. In an embodiment in which the mold cavities 24 are arranged inrectilinear transverse rows 22, the hopper 26 deposits the hardenablepaste 25 along a facing row 28 (see FIG. 7) of the plurality oftransverse rows 22 of mold cavities 24. The hopper 26 may include anopen upper portion 30 having an open top 32 and downwardly extending andconverging front and rear walls 34, 36, respectively. The hopper 26 mayinclude a central section 38 having front and rear walls 40, 42,respectively, shaped to form a trough with an arcuate bottom, and alower section 44 having downwardly and outwardly diverging forward andrearward lower walls 46, 48, respectively.

Front and rear walls 34, 36 of the hopper 26 define frontward andrearward facing surfaces, respectively. Side walls 40, 42 define forwardand rearward facing walls, respectively, and forward and rearward lowerwalls 48, 46 define forward and rearward facing walls, respectively. Thefront and rear walls 34, 36, side walls 40, 42, and forward and rearwardlower walls 46, 48 are closed at opposing sides by lateral walls 50, 52to define an interior chamber 54, as shown in FIGS. 5 and 6. Inembodiments, the hopper 26 includes a bottom panel 122 that in someembodiments is shaped to conform to the curvature of the outer peripheryof the drum 14. As will be described, in embodiments the arcuate shapeof the bottom panel 122 may support the remainder of the hopper 26 ontop of the drum 14, and in other embodiments, permit a close spacingbetween the hopper and the top of the drum.

In embodiments, the system 10 includes a support, generally designated56, which takes the form of a spool assembly having a spindle orrotating axle, for supporting a sheet 58 of open mesh, from a roll 60 onthe spool assembly 56, between the hopper 26 and the facing row 28 (seeFIG. 7) of the plurality of transverse rows 22 of mold cavities 24. Inembodiments, the spool assembly 56 includes a pair of posts 62 to whicha spindle or axle 63 is attached and extends therebetween. The support56 may be mounted on a rear platform 64 of the frame 12. In an exemplaryembodiment, the rear platform 64 is supported above the ground 66 by apair of rear wheels 68 and a pair of front wheels 70. In embodiments,the spindle 63 is mounted on the posts 62 for free rotation relative tothe support; in other embodiments the spindle is motorized to assist inpaying out the sheet 58 of open mesh.

In an embodiment, the sheet 58 of open mesh, is a sheet of geogrid, andin other embodiments is a sheet of open mesh made of a polymer, whichmay be a bi-axial geogrid material such as polyester or polypropylene.An example of such a polypropylene mesh is Fornit 30/30 geogridmanufactured by Huesker Inc. of Charlotte, N.C. In an embodiment, thesheet 58 of open mesh is fed forwardly, that is, to the left in FIG. 1,under guide tube 72, which is mounted on the frame 12 and extendstransversely adjacent the drum 14, and either over or under a transverseguide member 73, where it continues, passing beneath the hopper 26 andabove the drum 14.

A hardenable paste 25 deposited into the open top 32 of the hopper 26,and in an exemplary embodiment falls downwardly through the hopper andinto the facing row 28 of the plurality of transverse rows 22 where itis retained within the mold cavities 24. In embodiments, the hardenablepaste 25 is a fresh cement paste such as Portland cement, and in aparticular embodiment, is 5000 psi., wet-cast Portland cement. In otherembodiments, the hardenable paste 25 is selected from concrete, amixture of Portland cement, sand, and/or gravel, and a polymer. Thesheet 58 of open mesh becomes embedded in the hardenable paste 25 andthe combination of mesh and paste continues as the drum 14 rotates inthe direction of arrow A in a downstream direction away from the hopper26 where the paste hardens and the combination of mesh and paste leavesthe lower portion of the drum 14 as a flexible mat, generally designated74, of blocks 76 of hardened paste material held together by the sheet58 of geogrid mesh, also known as a tied concrete (i.e., hydraulicPortland cement) block mat when concrete is used as the hardenable paste25. A sheet of such a tied block mat is suitable for applying to theground for purposes of erosion control.

As shown in FIGS. 1, 2, 3, and 4, in an embodiment, a retaining plate,generally designated 78, extends partially about the outer periphery ofthe drum 14 and is positioned on the downstream side 80 of the drum andhopper 26. The retaining plate 78 may be spaced sufficiently close tothe outer periphery of the drum to retain the sheet 58 of open meshagainst the outer periphery of the drum and the hardenable paste 25within the mold cavities 24 passing between the retaining plate and theouter periphery of the drum 14.

In an embodiment, the retaining plate 78 may be shaped to conform to thecurvature of the outer periphery of the drum 14. Also in an embodiment,the retaining plate may be imperforate, comprising a single sheet ofcurved sheet metal. In other embodiments, the retaining plate 78 is madeof an aluminum alloy, or a woven or nonwoven mat of a geosynthetic, suchas polypropylene, a nylon, other polymers, a polyamide material, orcombinations of the foregoing. In the embodiment shown in FIGS. 1-4, theframe 12 supports the drum 14 and hopper 26, and the hopper ispositioned above an uppermost one of the plurality of transverse rows 22of mold cavities 24. Further, the retaining plate 78 may be attached tothe frame 12.

The retaining plate 78 may include an upper retaining member, generallydesignated 82, that may be attached to the frame 12 for holding an upperportion of the retaining plate 78 against the outer periphery of thedrum 14. The upper retaining member 82 may include an adjustableconnection, which may take the form of adjustable cables or chains 86,88 having ratchets incorporated therein for manually lengthening andshortening their lengths. The adjustable cables or chains 86, 88 mayextend from their upper ends, which may be attached to upright supports90, 92 of the frame 12 and are attached at their lower ends to the upperretaining member 82.

By adjusting the lengths of the cables or chains 86, 88, the spacingbetween the retaining plate 78 and the hopper 26 may be adjusted.Further, the spacing between the outer periphery of the drum 14 and theretaining plate 78 may be varied by adjusting the lengths of the cablesor chains 86, 88. In an embodiment, the upper retaining member 82 maytake the form of an upper retaining bar extending transversely of theretaining plate 78. Another function of the adjustable cables or chains86, 88 is that they may be lengthened or shortened to adjust the heightof the retaining plate 78 above the ground 66. This enables the point atwhich the flexible mat 74 is no longer held against the outer peripheryof the drum 14 and may begin to separate from the drum.

As shown in FIGS. 1-4, the system 10 may include a lower retainingmember 94 that holds a lower portion of the retaining plate 78 againstthe outer periphery of the drum 14. The lower retaining member 94 mayurge a lower edge of the retaining plate 78 against the drum 14 outerperiphery. In an embodiment, the lower retaining member 94 may take theform of a lower retaining bar or a round pipe that extends transverselyof the retaining plate 78. The lower retaining member 94 may includeleft and right adjustment arms 96, 98. The adjustment arms 96, 98 may beattached to the frame 12 and be adjustable in length to vary a forceexerted by the lower retaining member 94 against the retaining plate 78,and thus the force exerted by the retaining plate against a lowerportion of the outer periphery of the drum 14. The adjustment arms 96,98 may take the form a pair of adjustable straps, each attached to theframe 12.

In embodiments, the lower retaining member 94 may not be attached to theretaining plate 78, but only urged against it, thereby allowing relativeslidable movement between the lower retaining member and the shield, forexample, in response to height adjustment by cables or chains 86, 88. Insuch an embodiment, support chains 97, 99, each extending between andinterconnecting the lower retaining member 94 and the upright supports90, 92 of the frame 12, may support the lower retaining member 94 at apre-set, desired height above the ground 66 and relative to theretaining plate 78.

As shown in FIGS. 1 and 2, the retaining plate 78 may operate to holdthe sheet 58 of open mesh, which in an embodiment may be a geogrid orother geosynthetic material, against the outer periphery of the drum 14as the open mesh and rows 22 of mold cavities 24 pass beneath the hopper26 in a downstream direction, indicated by arrow A, away from the hopperand extend downwardly toward the ground 66. As the rows of mold cavities24 pass downstream of the hopper 26, they receive a hardenable paste 25,which in an embodiment may be fresh (i.e., flowable and not yethardened) cement paste, and the sheet 58 of geogrid open mesh may becomeembedded in the fresh cement paste, and the cement paste hardens as thedrum 14 rotates the combination mesh and cement paste between theretaining plate 78 and drum 14. At the lowermost portion of the drum 14,the paste 25 has hardened, in embodiments at least enough to bedimensionally stable, forming the mesh and block combination 75, alsoknown as a tied concrete block mat, shown in FIG. 1. In embodiments, thepaste 25 is formulated to continue to harden after the paste leaves themold cavities 24 as shown in FIG. 1.

As shown in FIGS. 1, 5, and 6, in an embodiment the hopper 26 includesan auger, generally designated 100, that is positioned in the centralsection 38 of the hopper. The auger 100 may be rotated by a motor 102and functions to distribute a hardenable paste 25, such as fresh cementpaste, along a length of the hopper 26. In an embodiment, the auger 100is co-extensive with the length of the facing row 28 of the plurality oftransverse rows 22 of mold cavities 24. In an embodiment, the auger 100includes a plurality of radially extending protrusions, generallydesignated 104, along its length. In an embodiment, the protrusionsinclude radially extending rods 106 and radially extending paddles 108arranged alternately along a central shaft 110. In an embodiment, therods 106 and paddles 108 extend radially from the central shaft 110 andare spaced about the periphery of the central shaft. In an embodiment,the central shaft 110 may be rotatably mounted in the end walls 50, 52of the hopper 26 (see FIG. 2).

In an exemplary embodiment, the paddles 108 include opposing flatsurfaces 112, 114 that are generally planar in shape and are orientedperpendicular, or generally perpendicular, to a central rotational axisof the central shaft 110, which is the same as the central axis of thetubular, rectilinear shaft. The surfaces 112, 114 of the paddles 108,are angled or skewed relative to the central axis of the central shaft110 to displace fresh cement paste deposited in an end of the hopper 26,along its length, to an opposite end of the hopper when the auger 100 isrotated, for example, clockwise as shown in FIGS. 5 and 6. The rods 106may include beveled ends 116 angled to provide close clearance with thecurved inner surface of the hopper 26, in contrast to squared or roundedends.

With the auger 100, the hopper 26 may be loaded with cement paste 25 ata loading end 118 (FIG. 2) that may be defined by an enlarged feed chute119. There is no need to distribute hardenable paste 25, such as freshcement paste, along the entire width of the open top 32 of the hopper26. Instead, fresh cement paste may be deposited in only a portion, orin embodiments at a single location, of the hopper 26, for example, intothe enlarged feed chute 119, and the auger 100 is rotated by the motor102 so that the angled paddles 108 rotate in the paste to urge anddistribute the paste along the length of the hopper 26, whereupon itfalls into the mold cavities 24 of the drum 14 through an opening 120.In an embodiment, the opening 120 is continuous along the length of thehopper and is formed in the bottom panel 122 of the hopper 26. In otherembodiments, the opening takes the form of spaced slots 120 that areshaped and aligned with the mold cavities 28.

In an embodiment, the paddles 108 may be distributed along the length ofthe auger 100 and may be attached to the central shaft 110 at regularlyspaced intervals. Also in an embodiment, the paddles 108 may bepositioned along the length of the central shaft 110 so that they arealigned with opening or slots 120 formed in the bottom panel 122 of thehopper 26 as shown in FIG. 6. As shown in FIGS. 5 and 6, the paddles 108and rods 106 may arranged in alternating relation along the length ofthe central shaft 110. In other embodiments, the paddles 108 may beangled to urge the paste from the center of the hopper 26 outwardly toboth sides or opposite ends of the hopper. With such an embodiment,paste may be deposited in a central region of the hopper 26—that is,midway or approximately midway between the ends 50, 52 of the hopper—androtation of the central shaft 110 may cause the paddles 108 to urge thepaste from the center of the hopper 26 to the ends of the hopper. Instill other embodiments, the paddles 108 may be angled to urge pastedeposited into the top 32 at any location along the length of the hopper26, and may be angled to urge the paste toward the ends 50, 52 of thehopper from the point at which the paste is deposited.

As shown in FIGS. 5, 6, and 7, in an embodiment, the hopper 26 includesa bottom panel 122. In an embodiment, the bottom panel 122 has anarcuate shape corresponding to a curvature of the drum 14. In anembodiment, the bottom panel 122 has an opening that takes the form ofspaced slots 120 that extend the length of the hopper 26. In anembodiment, the slots 120 may be shaped and positioned to align with themold cavities 124 of the transverse row 22 of mold cavities (a subset ofmold cavities 24 shown in FIGS. 4 and 8) of the facing row 28 of moldcavities of the drum 14. In an exemplary embodiment, the slots 120 areseparated by dividers 126. In still other embodiments, the slots 120have the same outer dimensions as at least some of the mold cavities 124that come into alignment with them as the drum 14 rotates relative tothe hopper 26. In other embodiments, the opening takes the form of acontinuous, unbroken slot 120 that extends the entire length, orsubstantially the entire length, of the hopper 26 and is co-extensivewith the arrangement of mold cavities 24 (FIG. 2) along the length ofthe drum 14. In still other embodiments, the opening is sized such thatthe slot 120 comprises the entire bottom of the hopper, eliminating thebottom panel 122.

An advantage of placing the slots 120 to align with the mold cavities124 is that the alignment minimizes waste of the fresh cement paste 25that is deposited in the hopper 26 by preventing fresh cement paste frombeing deposited between the mold cavities 124 on the outer periphery ofthe drum 14. As shown in FIGS. 5, 6, and 7, in an embodiment theplurality of slots 120 are arranged in a rectilinear row. In otherembodiments, the slots make a non-linear pattern along, or partiallyalong, the bottom panel 122. Each of the slots 120 may be of the sameouter dimensions as the corresponding mold cavity 124 of the facing rowof the plurality of rows 22 of mold cavities 24 formed on the outerperiphery of the drum 14 that may pass beneath it as the drum 14rotates.

As shown in FIGS. 1, 2, and 4, in an embodiment the hopper 26 issuspended from the upright supports 90, 92 of the frame 12. As shown inFIG. 2, in an embodiment the system 10 includes adjustable cables orchains 130, 132 that are attached to the upright supports 90, 92 andextend downwardly to be attached to the panel 122 in the bottom of thehopper 26. To maintain the hopper 26 in position directly above the 12o'clock position of the drum 14, in an embodiment the system 10 includesadjustable cables or chains 134, 136, that are attached at their upperends to the upper portion 30 of the hopper 26 and extend downwardly tobe attached at their lower ends to a transverse support beam 138 of theframe 12.

As shown in FIGS. 1 and 4, in an embodiment the hopper 26 is held inposition above the uppermost portion of the drum 14 by adjustable cablesor chains 140, 142 that are attached to posts 144, 146 of the frame 12.In an embodiment, the adjustable cables or chains 140, 142 also arelengthened and shortened to maintain the hopper 26 at the appropriateorientation above the drum 14. The clearance between the bottom panel122 of the hopper 26 and the upper portion of the drum 14 is adjusted byappropriately lengthening or shortening the adjustable chains 130, 132(see FIG. 2). With this structure, the hopper 26 may be suspended fromthe frame 12 to “float” above the upper portion of the drum 14, which inembodiments may be at approximately the 12 o'clock position, or in otherembodiments, rest on the top of the drum 14 with a pre-set amount ofweight force of the hopper.

The foregoing components of the system 10 for forming a flexible matprovide an efficient operation and minimize the waste produced. Theframe 12 may be moved by a separate device, such as a tractor or truck,so that, as the drum 14 rotates to deposit the finished flexible mat 74,the mat material is laid out on the ground 66 as a continuous sheet. Inan embodiment, as shown in FIG. 1, a tractor 200, which may take theform of a telehandler, may be connected to the transverse support beam138 by a cable 202 connected to a ring 204. In that embodiment, thetractor 200 may pull the frame 12 of the system 10 to the left in FIG. 1over the ground 66, which motion makes the drum 14 rotate in thedirection of arrow A, pulling the open mesh 58 from the spool assembly26, under guide tube 72, over guide member 73, and between the outerperiphery of the drum 14 and the underside of the bottom panel 122.

As the sheet 58 of open mesh, shown partially removed in FIG. 6 forclarity, passes beneath the hopper 26, the hardenable paste 25, whichhas been deposited into the hopper 26 and distributed by the auger 100along the length of the hopper, falls through the slots 120 into thecavities 124 (a subset of the cavities 24 shown in FIGS. 4 and 8) tofill the cavities. The sheet 58 of open mesh, which is held against theouter periphery of the drum 14 by the bottom panel 122 and the tensionof the mesh being payed out from the spool assembly 56 and the pinchbetween the bottom of the drum and the ground 66, becomes embedded inthe paste held in the cavities 124.

The combination of the sheet 58 of open mesh and paste is held againstthe outer periphery of the drum 14 and the paste within the cavities124, 24 as the transverse row 22 of mold cavities 124 rotate forwardlyof the bottom panel 122 by the retaining plate 78. By the time thetransverse row 22 of mold cavities 124 rotates beneath the retainingplate 78, the paste has hardened sufficiently to retain its shape as itfalls by gravity downwardly from the mold cavities to the ground 66,forming the flexible mat 74 (FIG. 1). Further hardening of the pasteinto the blocks 76 may occur after the flexible mat 74 has separatedfrom the drum 14 and been laid on the ground 66. The finished flexiblemat 74 may thereafter be rolled up and transported to a desiredlocation, where it may then be unrolled to form an erosion barrier.

After the flexible mat 74 has separated from the mold cavities 24,further rotation of the drum 24 brings the now-empty mold cavitiesupwardly to again pass beneath the hopper 26 to be overlaid with thesheet 58 of open mesh and receive hardenable paste 25 from the hopper26.

In an exemplary embodiment, the system 10 for making a flexible mat 74includes a form having a plurality of mold cavities 24, a panel 122having an opening 120, and a frame 12 that adjustably supports the panelabove the plurality of mold cavities and aligns the opening withadjacent ones of the mold cavities. The frame 12 spaces the panel abovethe mold cavities 24 a distance sufficient to receive the sheet 58 ofopen mesh between the panel 122 and the mold cavities. In the exemplaryembodiment shown in FIG. 1, the form is the drum 14 having the pluralityof mold cavities 24 formed in its outer cylindrical surface. Inembodiments, the opening 120 takes the form of a plurality of slots, asshown in FIG. 6. In embodiments, the panel 122, which is a part of thehopper 26, is adjustably supported above the mold cavities 24 of thedrum 14 by adjustable cables or chains 140, 142, and clearance betweenthe bottom panel 122 of the hopper and the upper portion of the drum,and hence the spacing of the panel above the mold cavities, is adjustedby lengthening or shortening the chains 130, 132 as well.

In an exemplary embodiment of the method for making a flexible mat 74using the system as described in the previous paragraph, the pluralityof mold cavities 24, which may be formed on the drum 14, is provided,and the panel 122 having an opening 120 is provided. The panel 122 ispositioned above the mold cavities 24 and the opening 120 is alignedwith adjacent or corresponding ones of the mold cavities. In anembodiment, positioning the panel 122 above the adjacent ones of themold cavities 24 includes adjusting a height of the panel above the moldcavities to a selected spacing between the panel and the mold cavitiesusing the adjusting chains 130, 132 and 140, 142. A sheet 58 of openmesh is placed between the panel 122 and the mold cavities 24, and ahardenable paste 25 is deposited through the opening 120 and into themold cavities such that the sheet of open mesh becomes embedded in thehardenable paste over the mold cavities. The hardenable paste 25 isallowed to harden into blocks 76 held together by the sheet 58 of openmesh, thereby forming the flexible mat 74, which in embodiments consistsof or comprises a tied block mat. The flexible mat 74 is then removedfrom between the panel 122 and the mold cavities 24.

Another embodiment of the disclosed flexible mat forming system,generally designated 300, is shown in FIG. 9. In an exemplaryembodiment, all of the components of the system 300 are identical instructure and function to their counterparts described with reference tothe system 10, and shown in FIGS. 1-8, except as otherwise described. Inan exemplary embodiment, the system 300 includes a frame 312 on which ismounted an elongate, rotatable cylindrical drum 314. In embodiments, thedrum 314 is rotated by a motor 316, which in embodiments is selectedfrom an electric motor and a hydraulic motor, in which case the system300 is self-propelled, or assists in propelling itself. In embodiments,the motor 316 rotates the drum 314 in a counterclockwise direction, asindicated by arrow A in FIG. 9. In other embodiments, system 300 doesnot have the motor 316, but instead the drum 314 rests on the ground 66and rotates in the direction of arrow A as a result of friction with theground from the frame 312 being pulled over the ground, which in FIG. 9is to the left, as indicated by arrow B by tractor 200. In anembodiment, the frame 312 includes a pair of horizontal beams 318, 320on which the drum 314 is rotatably mounted, for example by an axle, suchas a journal bearing 317.

Similar to the drum 14 shown in, for example FIG. 4, in an exemplaryembodiment, the drum 314 includes a plurality of mold cavities 324 thatare formed about the outer periphery, or cylindrical outer surface, ofthe drum. In other embodiments, the mold cavities 324 are arranged in apattern or patterns on the drum 314. In embodiments, the patterns areselected from a rectilinear, transverse row of the mold cavities, astaggered pattern of the mold cavities, a checked pattern of the moldcavities, a random pattern of the mold cavities, a running bond patternof the mold cavities, and combinations of the foregoing.

In embodiments the drum 314 takes the form of an elongated cylinder, andis a form having mold cavities 324. In embodiments, the mold cavities324 are shaped to receive hardenable paste 25 from the chute 27 from thedrum of a concrete transport truck, or from a concrete pump, or from aconcrete mixer trailer, all generally designated 310, and form thehardenable paste into blocks 76, which in embodiments may be square attheir base. For example, the mold cavities 24 are shaped to formpyramidal blocks 76 of hardenable paste 25 received from the hopper 26having square bases 6½″×6½″ and 2¼″ high, although in embodiments themold cavities have other shapes and/or dimensions, and varying shapesand/or dimensions. For example, the mold cavities 324 are shaped to formblocks 76 having shapes selected from rectangular, square, hexagonal,octagonal, round, elliptical, irregular, and combinations of theforegoing.

In an embodiment, the system 300 includes an elongate hopper, generallydesignated 326, adjacent the drum 314. In an embodiment, the hopper 326is positioned directly above the drum 314 at the 12 o'clock (i.e.,uppermost) position above the ground 66, such that the hopper ispositioned above uppermost ones of the plurality of the mold cavities324. In other embodiments, the hopper 326 is positioned relative to thedrum 314 upstream of the 12 o'clock position, for example at the 2o'clock position, and in still other embodiments, the hopper ispositioned relative to the drum downstream of the 12 o'clock position,for example at the 10 o'clock position. In other embodiments, the hopper326 is positioned adjacent the drum 314 in locations between the 3o'clock position and the 9 o'clock position.

In an embodiment, the hopper 326 is shaped to receive a hardenable paste25 and deposit the hardenable paste into mold cavities 324 facing thehopper. In an embodiment in which the mold cavities 324 are arranged inrectilinear transverse rows, the hopper 326 deposits the hardenablepaste 25 along a facing row, such as facing row 28 (see FIG. 7) of theplurality of transverse rows of mold cavities 324. In an embodiment, thehopper 326 is constructed identically to the hopper 26 shown in FIGS.1-7.

In an embodiment, a sheet 358 of open mesh is supported on the frame 312and moves with the drum 314. In a particular embodiment, the system 300includes a support, generally designated 356, which in embodiments takesthe form of a spool assembly having a spindle or rotating axle, forsupporting a sheet 358 of an open mesh, from a roll 360 on the spoolassembly, between the hopper 326 and a row of the plurality of moldcavities 24 facing the hopper. In embodiments, the support 356 includesa pair of posts 362 to which a spindle or axle 363 is attached andextends therebetween. In embodiments, the support 356 is mounted on arear platform 364 of the frame 312. In an exemplary embodiment, the rearplatform 364 is supported above the ground 66 by a pair of rear wheels68 and a pair of front wheels 70, as shown in FIG. 1 for rear platform64. In other embodiments, such as illustrated in FIG. 9, the rearplatform 364 is part of the frame 312 and is cantilevered rearwardlyfrom, and is attached to the journal bearing 317. In embodiments, thespindle 363 is mounted on the posts 362 for free rotation relative tothe support; in other embodiments the spindle is motorized to assist inpaying out the sheet 358 of open mesh. In other embodiments, the support356 takes the form of a shelf integral with or attached to the frame 312rearwardly of the drum 314, and the sheet 358 is stored on the shelf ina fan-folded stack.

In an embodiment, the sheet 358 of open mesh is sufficiently open toallow the hardenable paste 25 to flow from the hopper 326 through itinto the mold cavities 324. In embodiments, the open mesh is a sheet ofa polymer mesh, for example a bi-axial geogrid material comprised ofpolyester or polypropylene yarns. An example of such a polypropylenemesh is Fornit 30/30 geogrid manufactured by Huesker Inc. of Charlotte,N.C. That mesh has an aperture size of 1.35×1.35 inches (35×35 mm), amass per unit area of 7 oz/yd² (240 g/m²), and an ultimate wide widthtensile strength of 2,055 lb/ft (20 kN/m). In an embodiment, the sheet358 of open mesh is fed forwardly, that is, to the left in FIG. 9, whereit passes beneath the hopper 326 and above the drum 314, which inembodiments is at the 12 o'clock position relative to the drum.

A hardenable paste 25 deposited into the open top 332 of the hopper 326,and in an exemplary embodiment falls downwardly through the hopper andinto adjacent ones of the plurality of mold cavities 324, where it isretained within the mold cavities. In embodiments, the hardenable paste25 is a fresh cement paste such as Portland cement, and in a particularembodiment, is 5000 psi., wet-cast Portland cement. In otherembodiments, the hardenable paste 25 is selected from concrete, amixture of Portland cement, sand, and/or gravel, and a polymer.

The sheet 358 of open mesh becomes embedded in the hardenable paste 25and the combination of open mesh and paste continues as the drum 314rotates in the direction of arrow A in a downstream direction away fromthe hopper 326 where the paste hardens and the combination of open meshand paste leaves the lower portion of the drum 314 as a flexible mat,generally designated 74, of blocks 76 of hardened paste material heldtogether by the sheet 358 of open mesh, also known as a tied concrete(i.e., hydraulic Portland cement) block mat when concrete is used as thehardenable paste 25. A sheet of such a flexible mat 74 is suitable forapplying to the ground 66 for purposes of erosion control in suchapplications as hillsides, and stream, canal, and waterway embankmentsand beds.

In an embodiment, the system 300 includes a flexible sheet 302, which inembodiments is a plastic sheet, optionally imperforate, having anon-stick surface and a width the same as, or approximately the same as,the drum 314. In a particular embodiment, the flexible sheet 302 issingle wound clear polyethylene film, and in further embodiments is afilm composed of 100% virgin butene LLD resin. In embodiments, the sheet302 has a thickness of 1 mil. In an alternate embodiment, the flexiblesheet 302 is reinforced poly sheeting. In an embodiment, the flexiblesheet 302 is supported on the frame 312 to move with the drum 314.

In embodiments, a supply 304 of the flexible sheet 302 is mounted on theframe 312. In embodiments, the supply 304 is fan folded in a stack, andin other embodiments, the supply of the flexible sheet 302 is in theform of a roll, as shown in FIG. 9. In embodiments in which the supply304 of flexible sheet in the form of a roll, the support 306 is in theform of a spindle that is rotatably mounted on the frame 312 in front of(i.e., in the direction of movement of the drum 314 along arrow B), andoriented parallel to the rotational axis of, the drum. In embodiments inwhich the supply is in the form of a fan-folded stack, the support is inthe form of a shelf mounted on the frame 312.

In one embodiment, the supply in the form of a roll 304 is mounted onthe spindle 306 so that the flexible sheet 302 pays out from theunderside of the roll and passes over an idler bar 308 that extends thewidth of the flexible sheet 302. The idler roller 308 in embodimentstakes the form of a roller rotatably mounted on a support 310 that isattached to and extends upwardly from the frame 312, or a static,non-rotating pipe, rod, or bar oriented horizontally and mounted on thesupport 310. In embodiments, the support 310 is in the form of a pair ofupright members attached to the horizontal beams 318, 320 of the frame312. In embodiments, the idler bar 308 is positioned at or above the 9o'clock position relative to the drum 314, and the sheet passes over theidler bar so that it passes downwardly along the outer periphery of thedrum 314 to a pinch point 311 at the 6 o'clock position relative to thedrum, where it is pinched between the drum and the ground 66. In analternate embodiment, the spindle 306 is positioned where the idler bar308 is shown in FIG. 9, and the flexible sheet 302 is payed from the topof the supply 304 of the flexible sheet, which is in the form of a roll,downwardly over the outer surface of the drum 314 from the uppermostpoint of contact down to the pinch point 311.

In an embodiment, during operation of the system 300 shown in FIG. 9, asthe system 300 moves in the direction of arrow B, and the drum 314rotates relative to the ground 66 in the direction of arrow A, theflexible sheet 302 is payed off of the supply in the form of roll 304,over the idler bar 308 in the form of a roller, and extends about theouter surface of the drum 314 from the uppermost point of contact (at orabove the 9 o'clock position) down to the pinch point 311. Initially, itmay be necessary to rotate the roll 304 to remove an initial length ofthe flexible sheet 302 and feed it under the pinch point 311 beforefilling the mold cavities 324 with hardenable paste 25. As the drum 314rotates, the flexible sheet 302 is held against the outer surface of thedrum 314 by the tension caused by pulling the sheet tight by the pinchpoint 311, and the resistance to rotation of the roll 304 on the spindle306. In embodiments, the spindle 306 includes a clutch or frictionengagement that resists rotation to provide a desired level of tensionbetween the roll and the pinch point 311, and to prevent overrunning ofthe roll.

Thus, the flexible sheet 302 is held against the outer periphery of thedrum 314 and holds the hardenable paste 25 in the molds 324 and thesheet 358 of open mesh against the outer periphery of the drum so thatit remains embedded in the hardenable paste as the hardenable paste setsup and becomes dimensionally stable. In an embodiment, the flexiblesheet 302 is sufficiently wide to extend the entire width of the drum314 and cover all of the mold cavities 324. After the hardenable paste25 has hardened into the blocks 76 of the flexible mat 74, the flexiblesheet 302 is separated from the flexible mat as the mat is rolled intothe coil 390 shown in FIG. 8.

In an embodiment, the system 300 optionally includes a shield segment378 that is mounted on the frame 312 and is positioned adjacent the drum314 upstream of the point of initial contact between the flexible sheet302 and the drum. In one embodiment, the shield segment 378 is betweenthe point of initial contact between the flexible sheet 302 and thedownstream edge of the hopper 326. In an embodiment, like the retainingplate 78 of FIG. 1, the retaining plate segment 378 is rigid, and inparticular embodiments is made of sheet metal such as steel or aluminum,fiberglass, or a relatively thick, reinforced plastic such as nylon. Inan embodiment, the shield segment 378 is curved to conform to, and inembodiments have the same curvature and/or center of curvature as, theouter periphery of the drum 314 and is against the outer periphery ofthe drum to hold the hardenable paste 25 within the mold cavities 324and the sheet 358 of open mesh against the outer periphery of the drumso that it remains embedded in the hardenable paste within the moldcavities.

As shown in FIG. 10, a bridge or movable frame 380 includes an uppersurface, generally designated 382, which in embodiments is a metal grid,and front and rear supports 384, 386, respectively, which in embodimentsare pairs of wheels. The movable frame 380 includes a forward inclinedpanel 366 and a rearward inclined panel 368. The movable frame 380optionally includes a substantially horizontal middle panel 370 thatinterconnects the forward inclined panel 366 and rearward inclined panel368. In other embodiments, the forward and rearward inclined panels 366,368 meet to form an inverted “V” shape without the middle panel 370. Inan embodiment, each of the panels 366, 368, 370 is comprised of a pairof longitudinally extending parallel beams, such as I-beams, thatsupport a flat panel between them, which in embodiments may take theform of spaced parallel bars or rods extending transversely between thebeams. In an embodiment, the movable frame 380 is constructed as shownin commonly owned U.S. Pat. No. 10,161,094, the entire contents of whichare incorporated herein by reference.

In an embodiment, the process for making the sheet of flexible mat 74further includes lifting the flexible mat 74 from the ground 66 awayfrom the flexible sheet 302, after the hardenable paste 25 hassolidified into blocks 76, and placing the mat on the upper surface 382of the movable frame 380, as shown in FIG. 10. The movable frame 380 isthen moved in the direction of arrow C beneath the flexible mat 74,which remains substantially horizontally stationary, so that successiveportions of the mat slide over the upper surface 382 and are lifted upover as the movable frame is propelled beneath the sheet of the flexiblemat 74, which in embodiments is by a motor (not shown) integral with themovable frame, or propelling the frame by a tractor. This lifting of theflexible mat 74 over the angled intersections of the forward, rearward,and middle panels causes the mat to flex about a transverse axis. Thisflexing causes debrittlement of the flexible mat 74, in which excesspaste that may have flowed beyond the mold cavities 324 during themolding process is broken off from the blocks 74 and falls in the formof shards or chips 372 downwardly from the upper surface 382.

In an embodiment, the process for forming flexible mat shown in FIG. 9results in a flexible mat 74 that lies on top of the flexible sheet 302.With the process of debrittlement shown in FIG. 10, the flexible mat 74is separated from the flexible sheet 302 as it is lifted over the uppersurface 382, and the flexible sheet remains on the ground 66 below themovable frame 380. In an embodiment, the chips 372 fall down from theupper surface 382 onto the upper surface of the flexible sheet 302. Inan embodiment, the flexible mat 74 is subsequently rolled into a coil390, as shown in FIG. 8, and the coil transported to a site whereneeded. In an embodiment, the flexible sheet 302 also is rolled into acoil, thus capturing the chips 372, and disposed of.

The embodiments shown and described provide an efficient andcost-effective system and method for forming a tied flexible mat 74. Thecomponents of the systems 10, 300 are relatively low cost and arecapable of producing high volumes of flexible mat 74. While the methodsand forms of apparatus disclosed herein constitute preferred forms ofthe disclosed flexible mat forming system, it is to be understood thatthe system and invention are not limited to these precise formsapparatus and methods, and that changes may be made therein withoutdeparting from the scope of the disclosure.

What is claimed is:
 1. A system for forming a flexible mat having asheet of open mesh embedded in and interconnecting a plurality of blocksof a hardened paste, the system comprising: a rotatable drum having aplurality of mold cavities about an outer periphery thereof that receivea hardenable paste; a sheet of open mesh that is fed over the moldcavities so that the sheet of open mesh is embedded in the hardenablepaste deposited in the mold cavities; and a flexible sheet that isplaced against the outer periphery of the drum over the mold cavitiescontaining the hardenable paste and the sheet of open mesh of therotating drum to retain the hardenable paste within the mold cavitiesand retain the sheet of open mesh embedded in the hardenable paste asthe hardenable paste solidifies to form the flexible mat.
 2. The systemof claim 1, wherein the flexible sheet is a plastic sheet having anon-stick surface facing the mold cavities, and a width approximatelyequal to a width of the drum.
 3. The system of claim 2, wherein theflexible sheet is single wound polyethylene film.
 4. The system forforming a flexible mat of claim 1, wherein the flexible sheet is placedagainst the outer periphery of the drum between a 9 o'clock position anda 6 o'clock position relative to the drum.
 5. The system of claim 1,further comprising a frame, wherein the rotatable drum is attached tothe frame, and a supply of the sheet of open mesh and a supply of theflexible sheet are supported on the frame.
 6. The system of claim 5,wherein the sheet of open mesh is carried on the frame in a supply thatis selected from a fan-folded stack and a roll of the sheet of openmesh.
 7. The system of claim 6, further comprising a support for theroll of the sheet of open mesh, the support including spindle that isrotatably mounted on the frame downstream of the rotating drum.
 8. Thesystem of claim 7, further comprising an idler bar positioned at orabove a 9 o'clock position relative to the drum.
 9. The system of claim8, wherein the flexible sheet extends over the idler bar and downwardlyover an outer periphery of the drum.
 10. The system of claim 9, whereinthe flexible sheet extends from the supply to a pinch point at a sixo'clock position on the drum.
 11. The system of claim 5, furthercomprising a hopper for receiving the hardenable paste and depositingthe hardenable paste into the mold cavities along a length of the drum.12. The system of claim 11, wherein the hopper is positioned at a twelveo'clock position relative to the drum.
 13. The system for forming aflexible mat of claim 12, further comprising a support mounted on theframe, wherein the sheet of open mesh is fed from the support to alocation between the hopper and the mold cavities facing the hopper. 14.The system of claim 1, further comprising a rigid shield segmentpositioned adjacent the drum upstream of a point of initial contactbetween the flexible sheet and the drum.
 15. The system of claim 1,wherein the hardenable paste is selected from a fresh cement paste,optionally wet-cast Portland cement, concrete, a mixture of Portlandcement, sand, and/or gravel, and a polymer; and the sheet of open meshis a geogrid.
 16. A system for forming a flexible mat having a sheet ofopen mesh embedded in and interconnecting a plurality of blocks of ahardened paste, the system comprising: a frame; a cylindrical drumrotatably mounted on the frame and contacting the ground, the drumhaving a plurality of mold cavities about an outer periphery thereofthat receive a hardenable paste; a sheet of open mesh that is carried ona support mounted on the frame, the sheet of open mesh fed over the moldcavities so that the sheet of open mesh is embedded in the hardenablepaste deposited in the mold cavities; and a flexible sheet that iscarried on a roll mounted on the frame, the sheet placed against theouter periphery of the drum over the mold cavities containing thehardenable paste and the sheet of open mesh and extending downwardly toa pinch point between the drum the ground to retain the hardenable pastewithin the mold cavities and retain the sheet of open mesh embedded inthe hardenable paste as the hardenable paste solidifies to form theflexible mat.
 17. A method for forming a flexible mat having a sheet ofopen mesh embedded in and interconnecting a plurality of blocks of ahardened paste, the method comprising: rotating a drum having aplurality of mold cavities about an outer periphery thereof; depositinga hardenable paste in the mold cavities; feeding a sheet of open meshover the mold cavities so that the sheet of open mesh is embedded in thehardenable paste deposited in the mold cavities; and placing a flexiblesheet that is placed against the outer periphery of the drum over themold cavities containing the hardenable paste and the sheet of open meshto retain the hardenable paste within the mold cavities and retain thesheet of open mesh embedded in the hardenable paste as the hardenablepaste solidifies to form the flexible mat.
 18. The method of claim 17,further comprising separating the flexible sheet from the flexible mat.19. The method of claim 18, wherein separating the flexible sheet fromthe flexible mat includes lifting the flexible mat away from theflexible sheet to allow chips of the hardenable paste to fall downwardlyonto the flexible sheet.
 20. The method of claim 19, wherein lifting theflexible mat away from the flexible sheet includes passing a movableframe beneath the flexible mat and over the flexible sheet.